Table concentration of potash ores



Patented Jul 14, 1942 UNI'I'ED STATES 'PATENT: l 2,209,521 V TABLE CONCENTRATION or ro'rasn'oaas Francis x. Tami-on. Allen '1'. Cole, and James B. Dnke,.Mulberry, l-la., assignors' to Phosphate Recovery Corporation, New York, N. Y., a eorporation oi Delaware No Drawing. Application April 18, 1941,

SerialNo. 389,168

3 Claims. (01. 20949) The present invention relates to an improved process of concentrating on a shaking table, sylvite (potassium chloride) in coarse granular form, directly from sylvinite ore which consists principally of potassium chloride and sodium chloride.

The invention is particularly applicable to sylvinite ore found in the Carlsbad district 'of New Mexico. Prior to thepresent invention, efforts to concentrate sylvite in coarse granular form. from such ores by tabling operations have not been satisfactory as regards either the grades of concentrates produced or the of the sylvite in the ore.

The process of this invention is particularly useful in producing sylvite (potassium chloride) in the coarse granular form in which it is required for certain industrial purposes. Previously, this requirement had been met bybriquetting potassium chloride concentrates consisting of fine particles, and then crushing the briquettes. In the process of this invention, which is now in licensed use in the plant of Union Potash and Chemical Company, near Carlsbad,New Mexico, sylvite of the desired coarseness is produced directly from the ore.

some of the dimcult'ies and failures in efiorts to eifect table concentration of sylvite from sylvinite ores are described in a Report of Investigations of the United States Bureau of Mines, R. I. 3271, dated February 1935, which describes laboratory attempts to effect such concentration using as reagents crude oil in conjunction with (a) fatty acids, (b) fatty acid soaps, (c) aromatic sulphonates, and (d) sodium. and ammonium alkyl sulphates and related' compounds. It will be noted that said report definitely states that agents (a), (b) and (c) were found to be nonselective. As to reagents (d) sodium and ammonium alkyl sulphates and related compounds, the only reagent described in said report is what is called Emulsol reagent X-l the composition of which is not explained. Therefore, the teach-, ings of the said report are mostly negative and altogether vague as to the composition of the reagent used in the tests specifically described.

It will also be noted that all of the reagents (a) (b), (c) and (d) mentioned in said report are anionic surface active agents. So far as the inventors of the present process are aware, the

teachings of the said report have not been utilized in any practical concentration or sylvite from sylvinite ores. While crude oil or a related unsaponifiable water immiscible oil is used in percentages of recovery other compounds referred to in said report are employed.

The present improved tabling process is the re- I sult of the discover that if certain reagents,

hereinafter described, are used conjointly' with unsaponiiiable water immiscible oils (of which petroleum oils such as fuel oils, kerosene. etc., arepreferred on account of, theirlow cost) for the conditioning of adeslimed pulp of sylvinite crushed but coarse ore in a saturated solution of that ore, certain unique phenomena occur when such a conditioned pulp is fed to a shaking table; and the further discovery that such phenomena result in excellent separation on a shaking table of the sylvite (potassium chloride) constituents from the halite (sodium chloride) and other constituents of the ore. From observation of such a conditioned sylvinite ore on a shaking table, the said unique phenomena seem to consist in the separation of the sylvite particles from the halite particles of the pulp and the buoying of the sylvite particles within thev body and on the surface of the pulp,

. particles rise above and separate themselves from.

the process of the present invention, none of the as separate sylvite particles to which minute bubbles of air or gas are attached and as asglomerates of sylvite particles and air or gas bubbles, both of thwe being within the body of the pulp; and as skin-floated sylvite particles upon the surface of the pulp. As the pulp moves on the surface of the shaking table, the sylvite the halite particles, with the result that the sylvite particles pass oil at the side of the table while the halite particles are retained by the riliies and travel toward the end of the table where'they are discharged. The result is a sylvite concentrate of high grade, with recovery of a high percentage of the sylvite in the sylvinite ore.

The particular reagents which we have discovered will give satisfactory results when used in conjunction with unsaponiflable water immiscible oils, in the tabling operation above described, are cationic surface active agents such as aliphatic amines containing straight chain alkyl groups of at least 8 carbon atoms and preferably 12 carbon atoms, and salts of these amines. More particularly, we have found that octadecylamine acetate or commercial dodecylamine hydrochloride containing appreciable amounts of otheramine hydrochlorides having alkyl groups of about 8 to about 16 carbon atoms, each give particularly satisfactory results, as will-be apparent from the examples hereinafter described.

Since the constituents-of potash ores are soluble in water, a saturated solution of the potash in three ways, viz,

ore must be used in making the pulp for the practice of the invention. This saturated solution may be separated by well-known methods from the potassium chloride concentrates and the tailings and, mixed with fresh solid potash ore, may be used over again.

The ore, before being treated bythe process of this invention, should be crushed sufliciently to liberate a substantial proportion of the particles of potassium chloride, in the desired coarse granular form, from those of sodium chloride. It is. preferable not to crush the ore finer than about 5-mesh, if the potassium chloride particles are sufficiently free at that size, but it may be crushed to pass -mesh and still be considered as in coarse granular form. After the ore has been crushed, it should be substantially deslimed.

In the final step of separating the potassium chloride from the sodium chloride we have found shaking tables, such as Wilfley tables, satisfactory.

The following examples will illustrate the process of the invention as applied to a sylvinite ore from the Carlsbad district of New Mexico:

Example I.Sylvinite ore was crushed to minus 5 mesh, deslimed and made into a pulp of about 70% solids with a brine solution consisting of a saturated aqueous solution of the soluble constituents of thesylvinite ore. The pulp was mixed with 0.50 lb. of octadecylamine acetate and 6.16 lbs. of fuel oil per ton of dry ore and fed to a Wilfiey table. The potassium chloride passed over the side of the table was collected separately from the sodium chloride which came off at the end of the table. Two small middling products were taken off between the concentrates and tailings. The following table gives the results of the test:

, KClre- Product Vt eight K01 cove Percent Percent Percent K01 re- Product Weight K01 covers,

Percent Percent Percent Feed 100. 0 29. 8 100. 0 29. 3 93. 44 91. 6 2. 0 23. 47 l. 7 3. 7 2. 52 0. 3 64. l 2. 44 5. 6 0. 9 26. 10 0. 8

Example 3.--A similar sylvinite ore was crushed to minus 6-mesh and that portion remaining on a l i-mesh screen, after desliming, was made into a pulp at about'7.0% solids and mixed for about 1 minute with a commercial dodecylamine hydrochloride, containing appreciable amounts of other amine hydrochlorides having alkyl groups of from about 8 to about 16 carbon atoms, and fuel oil, at the rates of 3.5 lbs. and 4.0 lbs. per ton of ore, respectively. The thus conditioned pulp was then tabled in the manner described above, except that only one middling product was taken. The results were as shown in the following table:

KC] re- Product Weight KL] cove",

. Percent Percent Percent Feed 100.0 30.3 100.0 Concentr te 32. 8 85. 9 93. 2 Mlddll 2.1 1.1 0.5 Tail 03.0 2.1 as Slime 1. 5 7.8 0. 5

Example 4.'I'he process of the invention may also be used in the concentration of potassium chloride from potash ores containing minerals other than sylvinite as for example a potash ore from Carlsbad, New Mexico, which contained approximately 12% sylvite (potassium chloride), 37% halite (sodium chloride) and 46% langbeinite (potassium-magnesium sulphate). A charge of this ore was crushed to minus lO-mesh, deslimed and made into a pulp containing about 70% solids in the manner already described. It was mixed with octadecylamine acetate and fuel oil, at the rate of 1.0 lb. and 4.05 lbs. per ton of ore, respectively, and treated on a Wilfiey table. A concentrate was obtained containing 77.9% potassium chloride with a recovery of 78% of the potassium chloride in the original ore. This concentrate, of course, could have been improved in grade by retreatment.

While the invention has been described as carried out on a Wilfley table, we do not wish to limit ourselves to this form of apparatus but may employ any other form of apparatus adapted to separate the constituents of the ore by wet stratification methods.

What is claimed is:

1. The process of concentrating sylvite in coarse granular form directly from sylvinite ore, which comprises crushing the ore sufliciently to substantially liberate the sylvite particles in coarse granular form; substantially desliming said crushed ore; making said deslimed ore into a pulp with a saturated aqueous solution of the ore; conditioning said deslimed ore pulp with an oil immiscible with water and with a selective agent of the class of cationic surface-active agents consisting of aliphatic amines containing straight-chain alkyl groups of at least 8 carbon atoms; and subjecting the thus deslimed and conditioned sylvinite ore pulp to agitative wetstratifying classification on a shaking table from the side of which comes a coarse granular sylvite concentrate in the form of sylvite particles to which minute bubbles are attached, agglomerates of sylvite particles and bubbles, and skin-floated sylvite particles.

2. The process of concentrating sylvite in coarse granular form directly from sylvinite ore, which comprises crushing the ore sufficiently to substantially liberate the sylvite particles in coarse granular form; desliming said crushed ore; making said deslimed ore into a pulp with a saturated aqueous solution of the ore; conditioning said deslimed ore pulp with a petroleum oil and with octadecylamine acetate, and subjecting the thus deslimed and conditioned sylvinite ore pulp to agitative wet-stratifying classification on a shaking table from the side of which comes a coarse granular sylvite concentrate in the form of sylvite particles to which minute bubbles are attached, agglomerates of sylvite particles and bubbles, and skin-floated sylvite particles.

3. The process of concentrating sylvite in coarse granular form directly from sylvinite ore, which comprises crushing the ore sufliciently to substantially liberate the sylvite particles in coarse granular form; desliming said crushed ore; making said deslimed ore into a pulp with a saturated aqueous solution of the ore; condiof which comes a coarse granular sylvit-e concentrate in the form of sylvite particles to which minute bubbles are attached, agglomerates of sylvite particles and bubbles, and skin-floated 10 sylvite particles.

FRANCIS X. TARTARON. ALLEN T. COLE. JAMES B. DUKE. 

